1. Field of the Invention
This invention relates to electroptic processing, and more particularly in video detection of the orientation of labels on rotating containers utilizing digital processing and control techniques.
2. Description of the Prior Art
As an adjunct in consideration of the predication of the present invention, consider various well-known packaging and display practices of beverage bottles and cans, such as for soft drinks and beer. As is known, beverage bottles and cans are frequently marketed in cluster packages, such as the well-known six-pack, and the emerging two-pack of larger containers. The well-known six-pack may be a cardboard wrap, in which the ends are open; or it may be High-core (TM), in which cans are held together by a thin molded network of soft plastic; or in clear wrap, in which the containers are wrapped in a plastic which is then shrunk so as to grip them. In the latter two cases, there is no labeling of the cluster package, other than labeling on the individual containers therein; in the case of the cardboard wrap, cluster package labeling appears from a side view, but end view labeling is limited to the labeling on the individual containers. Quite obviously, since most round container labels (particularly bonded paper labels) cover only 120.degree. of the container periphery, there is a more than fifty percent chance that full product identification will not be readable on at least some of the containers when the cluster package is disposed on a shelf for viewing by consumers. It is therefore desirable and advantageous to rotate the containers before assemblage in the cluster package to ensure that any container labels which are to be used for product identification while on the display shelf are rotated in such a fashion that the label bearing product identification will be clearly visible to the consumer.
When orienting labels, the containers may be preclustered on the packaging machine and may be rotated the desired amount prior to arriving at the first packaging station. The container should be viewed in some fashion while being rotated, and the rotation ceased when the viewing apparatus detects that the package is in the proper position. The techniques of gripping and rotating containers have been well known for many years in the package handling arts. However, the technology of viewing and of processing resulting signals has heretofore left much to be desired. For instance, the technology for utilizing normal white light, which thereby permits the use of relatively inexpensive and highly available television-type equipment, is most advantageous; on the other hand, optical considerations -- such as reflections from minor flaws, changes in ambient light as a result of surrounding procedures, transients from many different sources and the like -- create difficulties in producing signals in response to ordinary white light. Additionally, the economics of beverage packaging are extremely critical; although it is certainly conceivable that a minicomputer could process any form of signal applied to it and determine when a bottle was oriented, the cost of such a computer relative to the production rate of packaging of six-packs and the like would be prohibitive, since the bottles would have to time share the computer, thereby reducing production rates below those which are permissible, or several computers would have to be used in order to properly orient the member containers in a cluster package such as a six-pack.